1. Field of the Invention
This invention relates to a video system arranged to pick up and record video images on a recording medium such as a magnetic tape or the like and to reproduce the recorded video images.
2. Description of the Related Art
FIG. 1 shows in a block diagram the recording system of the conventional camera-integrated type video tape recorder (hereinafter referred to simply as VTR).
In FIG. 1, a reference numeral denotes a video camera 1. A camera signal processing circuit 2 is arranged to process the output of the video camera 1. A numeral 3 denotes an amplifier 3 for a recording head 4. Although the recording head 4 is shown separately from a rotary drum 6 in the illustration, the recording head 4 is mounted on the rotary drum 6 in a position where a magnetic tape 5 is in contact with the head 4. The magnetic tape 5 is wrapped around the rotary drum 6.
A drum motor 7 is arranged to rotate the rotary drum 6. A capstan motor 8 is arranged to move the magnetic tape 5. A servo circuit 9 is arranged to control the drum motor 7 and the capstan motor 8. Although a reproducing head 10 is shown separately from the rotary drum 6 in the illustration, the reproducing head 10 is, in actuality, mounted on the rotary drum 6 also in a position where the magnetic tape 5 is in contact with the head 10.
A reproduction amplifier 11 is arranged to amplify the reproduction output of the reproducing head 10. A video signal processing circuit 12 is arranged to process a reproduced signal. A video output terminal 13 is provided for outputting a video signal to a monitor which is not shown. A system control circuit 14 is arranged to control the whole system. An input key part 15 is arranged to permit the operator to input an instruction for a desired operation mode.
A shooting operation is performed as follows. The operator first pushes a recording start key (or a shooting key) which is included in the input key part 15 for picking up a video image. The video image thus picked up by the video camera 1 is outputted in the form of an electrical signal. At the camera signal processing circuit 2, luminance and chrominance information is formed and outputted as a video signal. The level of the video signal is adjusted by the recording head amplifier 3. After the level adjustment, the video signal is recorded on the magnetic tape 5 through the recording head 4 mounted on the rotary drum 6.
In this instance, the control system of the VTR operates as follows: The input key part 15 informs the system control circuit 14 of the pushing operation on the recording start key. The system control circuit 14 then instructs the servo circuit 9 to act in a recording mode. In response to the instruction, the servo circuit 9 causes the drum motor 7 and the capstan motor 8 to rotate. The servo circuit 9 measures drum FG pulses which indicate the rotational frequency of the drum motor 7 (hereinafter referred to as DFG pulses) and FG pulses which indicate the rotational frequency of the capstan motor 8 (hereinafter referred to as CFG pulses). The drum motor 7 and the capstan motor 8 are controlled by the servo circuit 9 on the basis of the DFG and CFG pulses in such a way as to obtain rotational frequencies desired in the recording mode. The magnetic tape 5 is thus caused to travel at a speed for recording while the signal is recorded on the magnetic tape 5.
As a result of a recent trend of diversifying the functions of VTRs, some of VTRs have come to give special effects, such as an image fading, in processing images. FIG. 2 shows a VTR having the fading function. In this case, the VTR is arranged in the same manner as the arrangement shown in FIG. 1, except that the VTR includes a fading circuit 16 to which the output of the camera signal processing circuit 2 is applied.
With the VTR arranged as shown in FIG. 2, it operates as follows. When the recording start key is pushed, the video signal outputted from the camera signal processing circuit 2 with the luminance and chrominance information formed therein is allowed to pass the fading circuit 16 to be recorded on the magnetic tape 5 through the recording head amplifier 3 and the recording head 4 without being processed by the fading circuit 16 if the fading circuit 16 is in an inoperative state. In this instance, the control system operates in the same manner as in the case of the VTR shown in FIG. 1.
In a case where the operator wishes to bring a shooting operation to a stop while gradually decreasing the picture in a manner called "fade-out", the operator pushes a fade key which is included in the input key part 15. The input key part 15 then informs the system control circuit 14 that the fade key is operated. Upon receipt of this information, the system control circuit 14 instructs the fading circuit 16 to perform a fading action. In accordance with the instruction for fading, the fading circuit 16 causes the video signal to gradually converge to a predetermined value. After the lapse of a period of time required until the output of the fading circuit 16 converges to the predetermined value, the system control circuit 14 sends to the servo circuit 9 an instruction for bringing its recording action to a stop. The servo circuit 9 then causes the drum motor 7 and the capstan motor 8 to stop rotating and the recording operation comes to an end with the fade-out action. If the recording operation is to be resumed, the operator pushes the recording start key. Upon receipt of information on this, the system control circuit 14 instructs the servo circuit 9 to begin its action for commencement of recording.
The reproducing operation of the conventional VTR is described as follows. This description is given on the assumption that a video image recorded on the magnetic tape 5 is picked up by a video system arranged to watch the porch of a family residence.
Referring to FIG. 1 or FIG. 2, the operator pushes a reproduction key of the input key part 15. Then, the system control circuit 14 instructs the servo circuit 9 to act in a reproduction mode. In response to the instruction, the servo circuit 9 causes the drum motor 7 and the capstan motor 8 to rotate and measures or detects the DFG and CFG pulses which indicate the rotational frequencies (rotating speeds) of the motors 7 and 8.
The servo circuit 9 controls the drum motor 7 and the capstan motor 8, according to the DFG and CFG pulses, to have them rotate at the rotational frequencies desired in the reproduction mode. The video signal which is reproduced by the reproducing head 10 is then amplified by the reproduction amplifier 11. The amplified video signal is subjected to a demodulating process, an expanding process, etc., at the video signal processing circuit 12 and is thus converted into a video signal for the image to be displayed by a monitor. The video signal is outputted and supplied to the monitor through the video output terminal 13.
At the beginning of the reproducing operation, only an outside scene showing no one at the porch is usually reproduced. Therefore, the operator pushes a fast feeding key included in the input key part 15 for a fast feeding reproducing action. The system control circuit 14 then instructs the servo circuit 9 to act in a fast feeding reproduction mode. The servo circuit 9 controls the drum motor 7 and the capstan motor 8 to cause them to rotate at high speeds for the fast feeding reproduction.
While watching the video images on display in the fast feeding reproduction mode, the operator again pushes the reproduction key of the input key part 15 to change the fast feeding reproduction mode to a normal reproduction mode for confirmation when some image that shows someone as visiting the house begins to appear. When the visitor disappears, the VTR is again brought into the fast feeding reproduction mode by the operator and the steps of operation are repeated thereafter.
However, in the case of the conventional VTR shown in FIG. 1, if the shooting operation is to be carried out with the video camera or the VTR kept in a state of being fixedly mounted on a tripod and directed toward an object of shooting and waiting for a shooting opportunity, the operator is required to push a shooting key by continuously waiting in the same position.
Further, in a case where a VTR is used as a watch video system for watching a porch or the like, the shooting operation is continuously performed on an object which seldom shows any change. As a result, it has been impossible to carry out recording over a long period of time as the recordable length of the tape is limited.
Further, with the conventional VTR arranged as shown in FIG. 2, in a case where shooting and bringing the shooting to a stop are to be repeated with the VTR continuously directed toward shooting objects in a state of being fixedly mounted on a tripod, the operator is also required to push the fade key by continuously waiting in one and the same position.
Another problem with the conventional VTR lies in that, at the time of reproduction in this instance, the VTR necessitates the operator to alternately push the fast feeding key and the reproduction key. Such a reproducing operation has been very troublesome. Besides, the limited responsive speed of human being causes some time lag before the reproduction key is pushed after the presence of some person is found during the process of fast feeding reproduction. Then the time lag might cause some important scene to pass unnoticed.